package com.github.prontera.util;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.TimeUnit;

public class ThreadUtils {

	/**
	 * Uses the shutdown pattern from
	 * http://docs.oracle.com/javase/7/docs/api/java
	 * /util/concurrent/ExecutorService.html
	 * 
	 * @param pool
	 *            ExecutorService need to shutdown
	 * @param period
	 *            wait time period
	 * @param unit
	 *            wait time unit.
	 */
	public static void shutdownAndAwaitTermination(ExecutorService pool, long period, TimeUnit unit) {
		pool.shutdown(); // Disable new tasks from being submitted
		try {
			// Wait a while for existing tasks to terminate
			if (!pool.awaitTermination(period, unit)) {
				pool.shutdownNow(); // Cancel currently executing tasks
				// Wait a while for tasks to respond to being cancelled
				if (!pool.awaitTermination(period, unit))
					System.err.println("Pool did not terminate");
			}
		} catch (InterruptedException ie) {
			// (Re-)Cancel if current thread also interrupted
			pool.shutdownNow();
			// Preserve interrupt status
			Thread.currentThread().interrupt();
		}
	}
}
